From 0f7379157a9a1170ba611110d554d26770e3cf25 Mon Sep 17 00:00:00 2001
From: Norman Maurer <nmaurer@redhat.com>
Date: Thu, 30 Jan 2014 06:29:52 +0100
Subject: [PATCH] [#2168] Eliminate unnessary memory copy for heap buffers in
 JdkZlibEncoder

* Also adjust tests so it test with direct and heap buffers
---
 .../codec/compression/JdkZlibEncoder.java      | 18 +++++++++++++++---
 .../handler/codec/compression/ZlibTest.java    | 15 +++++++++------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
index e93354457a..aa46372643 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
@@ -196,8 +196,20 @@ public class JdkZlibEncoder extends ZlibEncoder {
             return;
         }
 
-        byte[] inAry = new byte[uncompressed.readableBytes()];
-        uncompressed.readBytes(inAry);
+        int len = uncompressed.readableBytes();
+        int offset;
+        byte[] inAry;
+        if (uncompressed.hasArray()) {
+            // if it is backed by an array we not need to to do a copy at all
+            inAry = uncompressed.array();
+            offset = uncompressed.arrayOffset() + uncompressed.readerIndex();
+            // skip all bytes as we will consume all of them
+            uncompressed.skipBytes(len);
+        } else {
+            inAry = new byte[len];
+            uncompressed.readBytes(inAry);
+            offset = 0;
+        }
 
         int sizeEstimate = (int) Math.ceil(inAry.length * 1.001) + 12;
 
@@ -222,7 +234,7 @@ public class JdkZlibEncoder extends ZlibEncoder {
             crc.update(inAry);
         }
 
-        deflater.setInput(inAry);
+        deflater.setInput(inAry, offset, len);
         while (!deflater.needsInput()) {
             deflate(out);
         }
diff --git a/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java b/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java
index 2d3bcda272..e9d3a5dff5 100644
--- a/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java
+++ b/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java
@@ -58,8 +58,7 @@ public abstract class ZlibTest {
         buf.release();
     }
 
-    private void testCompress0(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper, byte[] bytes) throws Exception {
-        ByteBuf data = Unpooled.wrappedBuffer(bytes);
+    private void testCompress0(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper, ByteBuf data) throws Exception {
         EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper));
 
         chEncoder.writeOutbound(data.copy());
@@ -74,7 +73,7 @@ public abstract class ZlibTest {
             chDecoderZlib.writeInbound(deflatedData);
         }
 
-        byte[] decompressed = new byte[bytes.length];
+        byte[] decompressed = new byte[data.readableBytes()];
         int offset = 0;
         for (;;) {
             ByteBuf buf = (ByteBuf) chDecoderZlib.readInbound();
@@ -89,7 +88,7 @@ public abstract class ZlibTest {
                 break;
             }
         }
-        assertArrayEquals(bytes, decompressed);
+        assertEquals(data, Unpooled.wrappedBuffer(decompressed));
         assertNull(chDecoderZlib.readInbound());
 
         // Closing an encoder channel will generate a footer.
@@ -137,11 +136,15 @@ public abstract class ZlibTest {
     }
 
     private void testCompressSmall(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
-        testCompress0(encoderWrapper, decoderWrapper, BYTES_SMALL);
+        testCompress0(encoderWrapper, decoderWrapper, Unpooled.wrappedBuffer(BYTES_SMALL));
+        testCompress0(encoderWrapper, decoderWrapper,
+                Unpooled.directBuffer(BYTES_SMALL.length).writeBytes(BYTES_SMALL));
     }
 
     private void testCompressLarge(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
-        testCompress0(encoderWrapper, decoderWrapper, BYTES_LARGE);
+        testCompress0(encoderWrapper, decoderWrapper, Unpooled.wrappedBuffer(BYTES_LARGE));
+        testCompress0(encoderWrapper, decoderWrapper,
+                Unpooled.directBuffer(BYTES_LARGE.length).writeBytes(BYTES_LARGE));
     }
 
     @Test